Explosive package



United States Patent Inventors Julian Michal Erazm Romocki Beloeil, Canada: Gordon Towell, Otterburn Heights, Quebec, Canada Appl. No. 766,701 Filed Oct. 11, 1968 Patented Oct. 20, 1970 Assignee Canadian Industries Limited Montreal, Quebec, Canada a Canadian corporation Priority Nov. 7, 1967 Canada EXPLOSIVE PACKAGE 10 Claims, 2 Drawing Figs.

US. Cl 102/24 F 42b 3/10 Field of Search ..102/22 24. 27: 86/ 20,3

[56] References Cited UNITED STATES PATENTS 3,357,355 12/1967 Roush 102/24 FOREIGN PATENTS 575,288 5/1959 Canada 102/24 667,051 7/1963 Canada 102/24 Primary Examiner-\'erlin R. Pendegrass Att0rneyBernard F, Roussin ABSTRACT: A double-wall thermoplastic film package for sensitive ammonium nitrate based explosive compositions which permits the explosive to be primed without the need to remove any component of the package. This is accomplished by providing a sealed bag having nonaligned slits in each wall through which the detonating means may be inserted.

INVENTORS Julian Mid-ml Eruzm RUMUCKI Gaidon TOWELL PATENT AGENT EXPLOSIVE PACKAGE This invention relates to a novel explosive package. More particularly, the invention relates to an improved package for relatively insensitive explosives for use in secondary blasting.

Explosive blasting agents based on oxygen-supplying salts such as, for example, ammonium nitrate and a sensitizer or fuel ingredient are widely known and used. The most well known of these comprises a blend of ammonium nitrate prills and fuel oil (AN/F explosives) wherein the ammonium nitrate is present in an amount of from about 92 percent to about 98 percent by weight of the total composition. Such AN/FO explosives, even when made with porous prills with a minimum amount of anticaking coating are generally insensitive to detonation by means of detonator caps or standard strengths of detonating cord and require the use of a booster of, for example, a 4 inch cartridge of high explosive or a small pentolite primer in order to ensure detonation. When, however, AN/FO explosives are crushed or pulverized so that about half the prills are broken to such an extent that they pass through a size 28 mesh Tyler screen, these blasting agents may be detonated with ease by means of, for example, two No. 8 blasting caps or about 6 inches of 50 grain detonating cord in a knotted or looped configuration.

The increased sensitivity of partially pulverized AN/FO blasting agents makes these explosives ideal for use as economic secondary blasting explosives. Another economic secondary blasting agent of sensitivity similar to crushed AN/FO explosives which may be employed is, for example, a

free-running or pourable mixture of fine grained oxygen-supplying salt, such as, for example, ammonium nitrate, which has been oxygen-balanced with dinitrotoluene and wax. Yet another suitable secondary blasting explosive comprises a slurry composition containing one or more oxygen-supplying salts, water, thickener and about 25 percent of particulate trinitrotoluene. Such compositions are well known in the art. By "secondary explosives is meant explosives which are employed for such purposes as breaking up large pieces of rock in quarry operations, the dislodgement of rock projections in underground workings and the like. Generally, in secondary blasting, the explosive charge is simply placed on the surface of the rock, jammed into rock crevices or held against the rock by means of props, poles and the like and thereafter detonated. Since, for example, in quarry operations a large number of secondary blasts may be required to fragment rock for subsequent crushing purposes, an economic explosive having simple detonating means is desirable. Sensitive, pulverized AN/FO blasting agent, or similar low cost explosives are therefore, ideal for this purpose.

Heretofore, secondary blasting explosives have been generally provided for use in thin-wall plastic (e.g. polyethylene) bags secured at the open end by means of a wire tie. The filled containers range from about 2 pounds to about 10 pounds in weight. in use at the blasting site, the blaster is required to remove the securing wire tie, insert the detonator cap and booster and then reseal the bag by means of the wire tie. Such procedures are not only time consuming but also present the hazard of open containers of explosives and the danger of accidental spillage of the contents of the package.

It is the object of the present invention to provide an improved explosive package for sensitive explosives.

It is a further object of the invention to provide a package for explosives by which such explosives may be primed without the need of removing any component of the package.

Other objects of the invention will become apparent hereinafter.

The improved explosive package of the invention comprises a double-ply, thermoplastic bag and a blasting explosive composition contained within said bag, said bag being sealed at one end and having a tied closure at the other end, the outer ply of the said bag having a slit therein of a size sufficient for passing therethrough a detonation means and the inner ply of the bag having a slit close to but not superimposed on the slit in said outer bag, the said inner ply slit being of a size sufficient for passing therethrough the said detonation means. Preferably the inner ply slit will lie in a plane degrees from the plane of the'outer ply slit.

The invention may be more fully understood by reference, to the accompanying drawing wherein FIG. 1 shows a view of a package made in accordance with the present invention and FIG. 2 shows a view of the package of FIG. 1 taken along line 2-2, primed with a detonation means.

Referring in detail to the FIGS. of the drawing. there is shows an explosive package 1 containing an explosive composition having an outer ply 2 of, for example, 4 mil polyethylene. An inner ply 3 of, for example, 4 mil polyethylene, is shown in contact with outer ply 2. Package 1 is heat sealed at the bottom end 4 and closed at the top end, by means of a wire tie 5. A slit 6 in a horizontal plane of a length suitable for the insertion of a detonation means is shown in outer ply 2. A slit 7 of size similar to slit 6 is shown in a vertical plane in ply 3. Slits 6 and 7 are not in overlapping or superimposed communications. Detonation means, for example, detonating cord 8 having a looped and knotted end 9 is shown passing through outer slit 6 and inner slit 7 so as to be in initiating contact with the contained explosive.

In use at the blasting site, the blaster will prepare a detonation means, for example, a loop of detonating cord or a detonating cap with attached electric leg wires or length of fuse, and insert the detonation means through the slit in the outer ply of the package. A small primer charge comprising, for example, a small or partial cartridge of conventional high explosive or a pentolite booster may sometimes be advantageously employed in conjunction with a detonating cap. The detonation means may then be threaded a short distance between the inner and outer plies of the package and thence pressed through the slit in the inner ply so as to be in full contact with the explosive contained within the bag. The package may then be placed ready for detonation by known means.

It can be noted that locations of the inner ply slit and outer ply slit are such that the possibility of leakage or loss of the contained explosive is remote. Since the package is substantially filled with explosive, the slits in the plies tend to remain closed during transportation and handling, yet no great resistance is presented to the insertion of the detonation means through the slits.

The double-ply bag of the explosive package of the invention may be simply fabricated in a wide range of sizes by conventional bag-making machinery. Thin-walled tubing of thermoplastic material of wall thickness of about 4 mils may be used. A number of flexible plastic materials combining high tensile and tear strength are known which may be used in the construction of the tubing and which will be obvious to those skilled in the art. A preferred material of construction is polyethylene having a wall thickness of from about 3 to about 8 mils although other plastics may be successfully employed. Appropriately placed slits may be made in the tubing, the inner tube then threaded through the outer tube and the double ply then heat-sealed and cut to size. If desired, the heatsealed bag corners may be furnished with a gusset. The bag may then be filled with sensitive explosive by known means and closed by means of a tie device, for example, a wire tie, hogring staple, tape, string, or the like. Alternatively, the double-ply package may be fabricated from two single bags cut to a required length and each having a sealed end and appropriately placed slits in the sidewalls thereof. The bags may then be assembled one inside the other with the slits close to but not superimposed on each other. The assembled bags may then be filled with the explosive mixture and tied closed.

The following Example illustrates the improved explosive package of the invention but the latter is in no manner to be limited in scope to the embodiments described.

EXAMPLE In a field trial at an underground mine, explosive packages of the invention were employed to remove rock projections in box hole cuts in the roof of the workings. Two-ply bags comprising 4 mil polyethylene in each ply and of dimensions 4 inches x 2 A inches x l l /2 inches were filled with a pulverulent AN/FO blasting agent and closed with a wire tie. The AN/FO blasting agent used contained 51 percent of material passing through 28 mesh Tyler screen and was made by passing regular production AN/FO between crusher rollers filled with shock absorbers having a spacing of 0.017 inches. The explosive packages each weighing 2 Va pounds were primed by means of knotted and looped ends of 50 grain detonating cord. The looped detonating cord end was pushed with the finger through the outer ply slit and then pressed through the inner ply slit. When the looped and knotted detonating cord end was pressed in place through the inner slit, removal of the primer was prevented. The thus primed explosive packages were tied with string to the end of long poles and lifted up so the explosive was in contact with the rock to be removed. No explosive sifted through the slits during these operations. Ten charges ranging in size from one package to four packages were fired and all performed satisfactorily.

We claim:

1. A blasting explosive package comprising a double-ply thermoplastic bag and a blasting explosive contained within said bag, said bag being sealed at one end and having a tie closure at the other end, the outer ply of said double-ply bag having a slit therein of sufficient length for the passing therethrough of a detonation means, the inner ply of said bag also having a slit therein of sufficient length for the passing therethrough of a detonation means, the said inner slit and outer slit being close together but not superimposed or in contact with each other.

2. An explosive package as claimed in claim 1 wherein the thermoplastic bag material is polyethylene.

3. An explosive package as claimed in claim 1 wherein the plane of said inner ply slit is degrees from the plane of said outer ply slit.

4. An explosive package as claimed in claim I wherein the said blasting explosive comprises a finely divided ammonium nitrate/fuel oil explosive.

5. An explosive package as claimed in claim 1 wherein the said blasting explosive comprises an inorganic oxygen-supplying salt oxygen-balance with dinitrotoluene and wax.

6. An explosve package as claimed in claim 1 wherein the said blasting explosive comprises an inorganic oxygen-supplying salt, water. thickener and from about 25 percent to about 35 percent by weight of particulate trinitrotoluene.

7. An explosive package as claimed in claim 4 wherein the finely divided ammonium nitrate/fuel oil explosive has a grain size wherein not less than 30 percent by weight of the total explosive passes through a size 28 mesh Tyler screen.

8. An explosive package as claimed in claim 1 wherein said detonation means comprises a loop of detonating cord.

9. An explosive package as claimed in claim 1 wherein said detonation means comprises a pentolite booster initiated by means of an attached detonator cap or detonating cord.

10. An explosive package as claimed in claim 1 wherein said detonation means comprises a conventional high explosive cartridge or part thereof initiated by means of an attached detonator cap or detonating cord. 

